1. Field of the Invention
The present invention relates to a suspension for supporting a flying type head slider providing a head element such as a thin-film magnetic head element or an optical head element, to a head gimbal assembly (HGA) with the suspension, and to a disk drive apparatus with the HGA.
2. Description of the Related Art
In a magnetic disk drive apparatus, thin-film magnetic head elements for writing magnetic information into and/or reading magnetic information from magnetic disks are in general formed on magnetic head sliders flying in operation above the rotating magnetic disks. The sliders are supported at top end sections of suspensions of HGAs, respectively.
Japanese patent publication 2001-057032A discloses such suspension with a load beam made of a thin stainless steel plate. The load beam has bends or ribs at both side ends thereof to enhance the bending stiffness.
For a magnetic disk drive apparatus used in a disk top type computer and a server type computer, a suspension with such structure can be adopted without any problem occurring. This is because such computers are immovably used, and therefore neither serious impact nor vibration is applied thereto. Whereas, for a smaller magnetic disk drive apparatus with a 2.5 inches or less disk to be mainly mounted on a portable computer, such suspension is insufficient in the impact resistance due to insufficient bending stiffness of its load beam.
In order to increase the bending stiffness of the load beam, Japanese patent publication 2002-352540A proposes using a multilayered metal sheet made of two metal films bonded by an adhesive or adhering sheet as the load beam, instead of a thin stainless steel plate.
However, even if such multilayered metal sheet is used as the load beam, because of the thin thickness of the metal sheet, it is quite difficult to satisfy the required bending stiffness of the load beam for the 2.5 inches or less magnetic disk drive apparatus. If metal sheets with an extremely high thickness are used as for the multilayered metal sheet, relatively high bending stiffness may be expected. However, in the latter case, the manufacturing cost of the suspension will greatly increase.